A "special collections book" can be many things. Age, rarity, value, and specialized content, are some factors that determine why a book is housed in special collections. Most often, the term refers to a rare book, dating from the dawn of European printing (ca 1456) to some point in the 19th century. A "special collections book" can also be a rare edition or special printing, published at a later date (anytime from 1900 to the present); such items are often referred to as the "book arts" or "fine press" materials. The nature and quality of a book's illustrations may be another factor - i.e if all of the illustrations are original prints by an important photographer. Condition is another determining factor; the "special collections" copy is, ideally, the "best," most complete, and most artifactual copy of a particular book.